When I generated 2nd order high pass filter in SigmaStudio , the “Read back function block” showed output signal of RMS very huge. and I used a Audio Analyzer, output noise still very huge around 400~600uV, (normal noise showed around 12~14uV). Seems only 2nd order high pass filter abnormal.
Can you help?
There is my testing results in SigmaStudio:
- Bypass mode: Okay.
- 1st order High pass filter Okay.
- 2nd order High pass filter : NG, noise value showed 400~600uV.
- 1st order Low pass filter: Okay.
- 2nd order Low pass filter: Okay.
Hardware : EVAL-ADAU1701 Rev.A ( Silicon Rev. ADAU1701 XSTZ#0605E)
Audio analyzer. (enable 20KHz LPF)
Software: SigmaStudio rev.3.1 build 9.